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Unknown fish disease!

Hi everyone, I need advice asap for my fish please as i dont have fish illness experience and they mean the world to me. I had 10 molly fish they are 1yr and 2months old (they were born in my tank) and last week they started to act strange... not interested in food as much just barely nibbling, hiding out in small groups in the bottom of the tank and just acting very skittish and not like themselves. We lost 2 mollies in one week.... i dont have any water testing kits (waiting for one to arrive in post currently) but took a sample of my water to local pet shop and they confirmed my water was good quality and suggested to add some aquarium salt for the mollies (which i purchased and have added a couple of times) So now this week, last night got home and one of my babies was struggling to swim he was showing severe signs of swimbladder (swimming vertically but actually flipping in circles slowly) at some points he was just lying on his back and it was pretty clear he was dying... there was another molly laying next to him in the corner of the tank... almost as family support it was heartbreaking. i tried to take him out to a seperate tank but he got extremely stressed and so did my other fish so i decided to leave him. This morning i checked them straight away and was shocked to see he was still alive struggling to breathe and just letting the current throw him around and even more shocked to see that the fish that had been supporting him was actually dead!!!!! The dead fish looked normal without any marks or injury or sign of disease (i had a look when i took him out of the tank) however the fish that was barely alive and struggling His tail had a white fluffy substance on it which was there last night a little bit greyish though, and today his tail was the half size of what it normally is so perhaps it could be rot fin? Around 4pm today this fish that was struggling died. I have 6 mollies in my tank and one common pleco named roger, i need advice to stop this disease from spreading which i believe it has already started, 3 of my molly fish have tiny white dots on them, just one dot in different places and i dont even know how to begin to research and treat this as alot of diseases are being suggested to me. I have attatched photos of the fish that died today (he is alive in these photos although he does not look it) and my fish with the small white spots on them if you look closely. Today i will do a 60% water change and change the substrate back to one they had before which is a natural aquarium soil (rogers favourite) . I really dont know what im supposed to do in a situation like this so please give as much advice as possible! Thanks in advance xIMG_8078.jpgIMG_8081.jpgIMG_8080.jpgIMG_8079.jpgIMG_8082.jpg

Re: Unknown fish disease!

Hi There

Can you please tell me what you have done to the tank in the last few days before this started …..as you have said that you have changed the substrate back to what it was ?

To me it looks like you may have upset the water chemistry because the beneficial bacteria that convert ammonia to relatively harmless nitrates live in the substrate and filters you have in the tank.....this in turn could weakened the fish immune system which in turn will cause stress and white spot.

Do you have water moment ….any oxygen going into the tank using a air line and air stone ?

60% water change is to much.... chlorine in the water could burn them....10% at a time should be enough.

Re: Unknown fish disease!

Hi guys,
So leading up to the death of the fish last week i did nothing apart from regular maintenance, i only did a 50% water change after the first 2 fish died as precaution. the substrate was changed following my water change this wednesday because it needed doing to be honest i had sand and when hoovering debris i left alot of the tank base bare so i took this opportunity to change back to a natural aquarium soil which the fish like. Ive also realised that i have been adding bottled water to my tank which was incorrectly advised to me by a fish shop owner in my area as our tap water is very hard. I know now that mollies actually thrive in hard water so my solution will be to slowly introduce tap water gradually back into the tank and hope it will help. Just not sure whether to do a mix of treated tap water and bottled water as my pleco roger prefers soft water and then the mollies will have some hardness from the tap? What do you guys think? I have a filter pump which created alot of water movement and also im using a small airstone as the mollies enjoy the bubbles!!! The salt that i added was the recommended dose for aiding disease which was 9g if i remember correctly which was added over a period of 3 days. I wont use the salt long term as i know roger doesnt like this. Last night the mollies ate a little bit of food for the first time in 3 days which is positive but one of them got seriously bloated and was swimming vertically displaying signs of swimbladder however today all the fish are swimming as normal without signs of stress. Two of the mollies still have a tiny white spot smaller than a needle point which isnt getting any bigger or smaller so im not sure if they are recovering? They dont look stressed
Thanks in advance

Re: Unknown fish disease!

It sounds as if you are getting there, it can be difficult to keep fish that are from different lakes/rivers together as you know some need hard and some need soft water but they can be acclimatised .I used to let my water stand over night so the temp ect was the same as the tank water but if you have a heater and some dechlorinator you should not need to do that . Fingers crossed let us know how you get on , what ever changes you make do them gradually the last thing you want is to stress your fish any more . I would think the soil is a good idea bear in mind that can change the hardness/softness of the water as well remember lots of pics

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Re: Unknown fish disease!

So as suggested to me today i have started there first treatment of melifix for bacterial infections, doing research alot of people are saying it wont actually cure disease that is already there and also that it is a waste of time. Should i continue to use it for 7 days as the bottle says? Or not? Also the fish that was displaying the signs of swim bladder but was fine yesterday, today he is starting to float around the tank again so im a bit worried, I initially thought as they didnt eat for 3 days due to sickness that he had been a bit of a piggy on thurs evening when they did eat but as he was fine yesterday i fed them the smallest ammount of food which they werent really interested in.... should i switch feeding to once every 2 days until he is swimming as normal? I will try to feed them de shelled peas again as i have in past but they NEVER eat it!! On a more positive note the white spots from the mollies seems to have disappeared apart from a slight shading on one of the molly fish but they wont stay still long enough for me to take a photo 🤣 have attatched photos of the fish struggling to swim so let me know what you think!!!! First pic where he is literally vertical was thurs evening and the ones IMG_8119.jpgIMG_8122.jpg4bc7a2f1-eb9f-4e06-ae8b-3828d5344bb6.jpgIMG_7912.jpgwhere he is at an angle was taken a moment ago!
Also threw in a couple of photos of roger, one a week or so after we got him and one taken about a month ago!!!! Love him so much!!!!

Re: Unknown fish disease!

Sorry not been around over the weekend as I've no PC at home until a new power supply arrives for it

To be honest I would stop using the melifix as I too think it is a waste of time. It sounds like you are now getting back on top of things. Please stop using bottled water as you don't know what is in it.

I would make sure that you get yourself a test kit and do tests a couple of times a week so that you get used to it and under stand how the water chemistry can change day by day when feeding and doing any water changes to the tank. One thing you have not said (Heater) I presume you have a heater in there and it is set between 75ºF and 82ºF or 24ºc

You should fed them every single day but not to much, try feeding your mollies some live food as they will love this and will get them moving around and change the food you give them from day to day like brine shrimp, bloodworms and daphnia and tropical flakes.

Re: Unknown fish disease!

Hi no worries & thanks for getting back to me. So yeah i have a heater its on 26oC should i turn it down to 24? I have been feeding them daily but today one of my molly fish is just laying around on his side alot unless i come near him he swims around a bit more normal, he has a different pattern than normal almost like his scales are coming off (just a couple as it sounds very dramatic) he isnt bullied, my tank is friendly. As im writing this he has put himself in a small gap in the side of my tank next to filter... a couple of my fish have gone here to die... please i need advice is there something i can add to the water to boost there health? Or any other recommendations on what to do..... he doesnt look good and i dont think he will make the night...
Thanks...